1. Field of the Invention
This invention concerns a process for treating a mixture of coal and paraffinic feedstock to yield thermally cracked, demetallated and partially denitrogenated product oils.
2. Description of the Prior Art
Co-processing coal and petroleum residua has so far found only limited application in the fuel industry. For example, coal can be employed as a site for coke and metals deposition to prevent reactor fouling and to enhance demetallation processes. In addition, reacting coal with a petroleum residua under certain conditions can produce highly desirable liquids or carbonaceous pitch products which are valuable as a blending agent for enhancing the production of metallurgical coke from coals that are otherwise unsuitable for such purposes.
U.S. Pat. No. 3,840,456 (Yavorsky et al.) dated Oct. 8, 1974 discloses a coal desulfurization process in which coal reacts with heavy petroleum oils under heat and pressure in the presence of a reducing gas.
U.S. Pat. No. 4,054,504 (Chervenak et al.) dated Oct. 18, 1977 disclosed a process for simultaneously converting coal and crude oil into liquid fuel in an ebullated bed catalytic reactor.
U.S. Pat. No. 4,081,351 (Heineman) dated Mar. 28, 1979 discloses a method for converting coal into a denitrified liquid fuel product.
U.S. Pat. No. 4,176,041 (Mori et al.) dated Nov. 27, 1979 discloses a catalytic process for reacting low grade coal having an ash content of no more than 5 weight percent in the presence of a heavy oil to a carbonaceous material suitable for production of metallurgical coke.
U.S. Pat. No. 4,152,244 (Raichle et al.) dated May 1, 1979 discloses a process for hydrocracking coal in the presence of process-derived middle and heavy oils.
U.S. Pat. No. 4,151,066 (Yan) dated Apr. 24, 1979 discloses a process for combining coal and a highly aromatic petroleum residua.
Similarly related patents are U.S. Pat. No. 4,018,663 (Karr, Jr.) dated Apr. 19, 1977 and U.S. Pat. No. 4,111,787 (Aldridge et al.) dated Sept. 5, 1978.
There remains a pressing need for new technology in the conversion of coal into high value liquid carbonaceous products to complement and to enhance conventional petroleum derived energy applications. Further, there is a need for liquified coal products which qualify as premium, high octane gasolines.
The present invention proposes the separation of asphaltenic fractions containing coal derived and other high molecular weight materials from the paraffinic liquid products of petroleum residua. This separation procedure is advantageous to the further processing of thermally cracked, demetallated and partially denitrogenated product oils. In addition, this separation process yields a separate carbonaceous pitch product. Such a pitch is valuable as a blending agent for enhancing the production of metallurgical coke from coals that are otherwise unsuitable for such purposes.